One type of track for the gravity feeding of packages or bottles from the back to the front of a shelf on a display stand is represented by U.S. Pat. No. 2,218,444 issued Oct. 15, 1940, which discloses a metal channel intended primarily for use in conjunction with milk bottles in refrigerators. The metal channel does not lend itself well for economical production procedures.
Another type of gravity feed device includes a downwardly tilted planar support surface over which a plastic feeder belt is arranged to slide as disclosed in U.S. Pat. No. 4,128,177 issued Dec. 5, 1978. As each shelf of a display stand needs several such devices each of which includes a belt, support surface and two rollers, the construction of a display stand utilizing such devices is complicated and involves costly construction.
It has been recognized for a long time that it would be economical to construct a gravity feed track of plastic. However, the coefficient of friction of these plastics was so high that an excessive tilt of the track was required for bottles or packages to slide. Excessive tilt to the track can result in the bottles falling rather than sliding.
Organopolysiloxane release fluids for use as mold release agents have been known for a long time as illustrated by U.S. Pat. No. 2,666,685 issued on Jan. 19, 1954. This mold release composition, which also included other ingredients, was applied to the mold each time an article was molded. To eliminate the labor and time involved in spraying the release agent on the mold each time, it is now common to incorporate a small amount of certain mold release agents, such as a dimethylpolysiloxane fluid, in the plastic resin being molded. The dimethylpolysiloxane fluid not only aids in the release of the resin from the mold but also sometimes aids in the processability of the resin. Dimethylpolysiloxane fluid is normally added to resins in an amount from approximately 0.1 to 0.25 percent by weight of the resin. The addition of dimethylpolysiloxane fluid to various resins is disclosed in Dow Corning Bulletin 22-290 dated 9/74. Tracks formed of a combination of high impact polystyrene and silicone are disclosed in U.S. patent application No. 098,876 entitled "Gravity Feed Shelf" filed Nov. 30, 1979, now U.S. Pat. No. 4,314,648.